Compound and organic light emitting device using the same

ABSTRACT

Disclosed is an organic light emitting device. The organic light emitting device comprises a first electrode, organic material layer(s) comprising a light emitting layer, and a second electrode. The first electrode, the organic material layer(s), and the second electrode form layered structure and at least one layer of the organic material layer(s) include the compound of Formula 1 or the compound of Formula 1 into which a thermosetting or photo-crosslinkable functional group is introduced.

This application claims priority to International Application No.10-PCT/KR2005/003175, filed on Sep. 23, 2005, and Korean PatentApplication No. 10-2004-0077245, filed on Sep. 24, 2004, which arehereby incorporated by reference in their entirety.

TECHNICAL FIELD

The present invention relates to an organic light emitting device whichcomprises a fluorene derivative capable of significantly improving alifespan, efficiency, and electrochemical and thermal stabilitiesthereof.

BACKGROUND ART

An organic light emission phenomenon is an example of a conversion ofcurrent into visible rays through an internal process of a specificorganic molecule. The organic light emission phenomenon is based on thefollowing mechanism. When an organic material layers are interposedbetween an anode and a cathode, if voltage is applied between the twoelectrodes, electrons and holes are injected from the cathode and theanode into the organic material layer. The electrons and the holes whichare injected into the organic material layer are recombined to form anexciton, and the exciton is reduced to a bottom state to emit light. Anorganic light emitting device which is based on the above mechanismtypically comprises a cathode, an anode, and organic material layer(s),for example, organic material layers including a hole injection layer, ahole transport layer, a light emitting layer, and an electron transportlayer, interposed therebetween.

The materials used in the organic light emitting device are mostly pureorganic materials or complexes of organic material and metal. Thematerial used in the organic light emitting device may be classified asa hole injection material, a hole transport material, a light emittingmaterial, an electron transport material, or an electron injectionmaterial, according to its use. In connection with this, an organicmaterial having a p-type property, which is easily oxidized and iselectrochemically stable when it is oxidized, is mostly used as the holeinjection material or the hole transport material. Meanwhile, an organicmaterial having an n-type property, which is easily reduced and iselectrochemically stable when it is reduced, is used as the electroninjection material or the electron transport material. As the lightemitting layer material, an organic material having both p-type andn-type properties is preferable, which is stable when it is oxidized andwhen it is reduced. Also a material having high light emissionefficiency for conversion of the exciton into light when the exciton isformed is preferable.

In addition, it is preferable that the material used in the organiclight emitting device further have the following properties.

First, it is preferable that the material used in the organic lightemitting device have excellent thermal stability. The reason is thatjoule heat is generated by movement of electric charges in the organiclight emitting device. NPB, which has recently been used as the holetransport layer material, has a glass transition temperature of 100° C.or lower, thus it is difficult to apply to an organic light emittingdevice requiring a high current.

Second, in order to produce an organic light emitting device that iscapable of being actuated at low voltage and has high efficiency, holesand electrons which are injected into the organic light emitting devicemust be smoothly transported to a light emitting layer, and must not bereleased out of the light emitting layer. To achieve this, a materialused in the organic light emitting device must have a proper band gapand a proper HOMO or LUMO energy levels. A LUMO energy level ofPEDOT:PSS, which is currently used as a hole transport material of anorganic light emitting device produced using a solution coating method,is lower than that of an organic material used as a light emitting layermaterial, thus it is difficult to produce an organic light emittingdevice having high efficiency and a long lifespan.

Moreover, the material used in the organic light emitting device musthave excellent chemical stability, electric charge mobility, andinterfacial characteristic with an electrode or an adjacent layer. Thatis to say, the material used in the organic light emitting device mustbe little deformed by moisture or oxygen. Furthermore, proper hole orelectron mobility must be assured so as to balance densities of theholes and of the electrons in the light emitting layer of the organiclight emitting device to maximize the formation of excitons.Additionally, it has to be able to have a good interface with anelectrode including metal or metal oxides so as to assure stability ofthe device.

Accordingly, there is a need to develop an organic light emitting deviceincluding an organic material having the above-mentioned requirements inthe art.

DISCLOSURE OF INVENTION Technical Problem

Therefore, the object of the present inventions is to provide an organiclight emitting device which is capable of satisfying conditions requiredof a material usable for an organic light emitting device, for example,a proper energy level, electrochemical stability, and thermal stability,and which includes a fluorene derivative having a chemical structurecapable of playing various roles required in the organic light emittingdevice, depending on a substituent group.

Technical Solution

The present invention provides an organic light emitting device whichcomprises a first electrode, organic material layer(s) comprising alight emitting layer, and a second electrode, wherein the firstelectrode, the organic material layer(s), and the second electrode forma layered structure and at least one layer of the organic materiallayer(s) includes a compound of the following Formula 1 or a compound ofFormula 1 into which a thermosetting or photo-crosslinkable functionalgroup is introduced:

In Formula 1, X is C or Si, and A is —NZ1Z2.

Y is a bond; bivalent aromatic hydrocarbons; bivalent aromatichydrocarbons which are substituted with at least one substituent groupselected from the group consisting of nitro, nitrile, halogen, alkyl,alkoxy, and amino groups; a bivalent heterocyclic group; or a bivalentheterocyclic group which is substituted with at least one substituentgroup selected from the group consisting of nitro, nitrile, halogen,alkyl, alkoxy, and amino groups.

Z1 and Z2 are each independently hydrogen; aliphatic hydrocarbons havinga carbon number of 1-20; aromatic hydrocarbons; aromatic hydrocarbonswhich are substituted with at least one substituent group selected fromthe group consisting of the nitro, nitrile, halogen, alkyl, alkoxy,amino, aromatic hydrocarbon, and heterocyclic groups; a silicon groupsubstituted with aromatic hydrocarbons; a heterocyclic group; aheterocyclic group which is substituted with at least one substituentgroup selected from the group consisting of the nitro, nitrile, halogen,alkyl, alkoxy, amino, aromatic hydrocarbon, and heterocyclic groups; athiophenyl group which is substituted with hydrocarbons having a carbonnumber of 1-20 or aromatic hydrocarbons having a carbon number of 6-20;or a boron group which is substituted with aromatic hydrocarbons.

R1 to R11 are each independently hydrogen, a substituted orunsubstituted alkyl group, a substituted or unsubstituted alkoxy group,a substituted or unsubstituted alkenyl group, a substituted orunsubstituted aryl group, a substituted or unsubstituted arylaminegroup, a substituted or unsubstituted heterocyclic group, an aminogroup, a nitrile group, a nitro group, a halogen group, an amide group,or an ester group. R1 to R11 may form aliphatic or hetero condensationrings along with adjacent groups.

R12 to R15 are each independently hydrogen, a substituted orunsubstituted alkyl group, a substituted or unsubstituted alkoxy group,a substituted or unsubstituted alkenyl group, a substituted orunsubstituted aryl group, a substituted or unsubstituted heterocyclicgroup, an amino group, a nitrile group, a nitro group, a halogen group,an amide group, or an ester group. R12 to R15 may form aliphatic orhetero condensation rings along with adjacent groups.

R7 and R8 may be directly connected to each other, or may form acondensation ring along with a group selected from the group consistingof O, S, NR, PR, C═O, CRR′, and SiRR′. R and R′ are each independentlyor collectively hydrogen, a substituted or unsubstituted alkyl group, asubstituted or unsubstituted alkoxy group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted aryl group,a substituted or unsubstituted arylamine group, a substituted orunsubstituted heterocyclic group, a nitrile group, an amide group, or anester group, and may form a condensation ring to form a spiro compound.

A detailed description will be given of the substituent groups ofFormula 1.

In Z1 and Z2 as the substituent groups of Formula 1, the aromatichydrocarbons are exemplified by monocyclic aromatic rings, such asphenyl, biphenyl, and terphenyl, and multicyclic aromatic rings, such asnaphthyl, anthracenyl, pyrenyl, and perylenyl. The heterocyclic group isexemplified by thiophene, furan, pyrrole, imidazole, thiazole, oxazole,oxadiazole, thiadiazole, triazole, pyridyl, pyridazyl, pyrazine,quinoline, and isoquinoline.

Examples of aliphatic hydrocarbons having a carbon number of 1-20include straight chain aliphatic hydrocarbons, branched chain aliphatichydrocarbons, saturated aliphatic hydrocarbons, and unsaturatedaliphatic hydrocarbons. They are exemplified by an alkyl group, such asa methyl group, an ethyl group, an n-propyl group, an iso-propyl group,an n-butyl group, a sec-butyl group, an iso-butyl group, a ter-butylgroup, a pentyl group, and a hexyl group; an alkenyl group having adouble bond, such as styryl; and an alkynyl group having a triple bond,such as an acetylene group.

The carbon number of the alkyl, alkoxy, and alkenyl groups of R1 to R15of Formula 1 is not limited, but is preferably 1-20.

The length of the alkyl group contained in the compound does not affectthe conjugate length of the compound, but may affect the method ofapplying the compound to the organic light emitting device, for example,a vacuum deposition method or a solution coating method.

Illustrative, but non-limiting, examples of the aryl group of R1 to R15of Formula 1 include monocyclic aromatic rings, such as a phenyl group,a biphenyl group, a terphenyl group, and a stilbene group, andmulticyclic aromatic rings, such as a naphthyl group, an anthracenylgroup, a phenanthrene group, a pyrenyl group, and a perylenyl group.

Illustrative, but non-limiting, examples of the arylamine group of R1 toR11 of Formula 1 include a diphenylamine group, a dinaphthylamine group,a dibiphenylamine group, a phenylnaphthylamine group, aphenyldiphetylamine group, a ditolylamine group, a phenyltolylaminegroup, a carbazolyl group, and a triphenylamine group.

Illustrative, but non-limiting, examples of the heterocyclic group of R1to R15 of Formula 1 include a thiophenyl group, a furan group, apyrrolyl group, an imidazolyl group, a thiazolyl group, an oxazolylgroup, an oxadiazolyl group, a triazolyl group, a pyridyl group, apyradazine group, a quinolinyl group, an isoquinoline group, and anacridyl group.

In addition, illustrative, but non-limiting, examples of the alkenyl,aryl, arylamine, and heterocyclic groups of R1 to R15 of Formula 1include groups shown in the following Formulae.

In the above Formulae, Z is a group selected from the group consistingof hydrogen, aliphatic hydrocarbons having a carbon number of 1-20, analkoxy group, an arylamine group, an aryl group, a heterocyclic group, anitrile group, and an acetylene group. Examples of the arylaamine, aryl,and heterocyclic groups of Z are as shown in the above-mentionedsubstituent groups of R1 to R15.

According to a preferred embodiment of the present invention, X ofFormula 1 is C, and R7 and R8 are directly connected to each other, orform a condensation ring along with a group selected from the groupconsisting of O, S, NR, PR, C═O, CRR′, and SiRR′ (R and R′ are asdefined in Formula 1).

According to another preferred embodiment of the present invention, X ofFormula 1 is Si, and R7 and R8 are directly connected to each other, orform a condensation ring along with a group selected from the groupconsisting of O, S, NR, PR, C═O, CRR′, and SiRR′ (R and R′ are asdefined in Formula 1).

According to still another preferred embodiment of the presentinvention, the compound of Formula 1 may be any one of Formulae 2 to 5.

In the above Formulae, A is as defined in Formula 1.

Illustrative, but non-limiting, examples of the A group of Formula 1 areas follows. Combination of the compounds of Formulae 2 to 5 and thefollowing group A can form various derivatives. For example, if thecompound of Formula 2 is combined with the group 1, the resultingproduct will be designated by the compound of Formula 2-1.

[A Group]

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an organic light emitting device comprising asubstrate 1, an anode 2, a light emitting layer 3, and a cathode 4; and

FIG. 2 illustrates an organic light emitting device comprising asubstrate 1, an anode 2, a hole injection layer 5, a hole transportlayer 6, a light emitting layer 7, an electron transport layer 8, and acathode 4.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a detailed description will be given of the presentinvention.

Various substituent groups are introduced into a core structure shown inFormula 1, in detail, the core structure in which a fluorene group isbonded to a combination of an acridine group and a carbazolyl group toform a spiro structure, thereby the compound of Formula 1 hascharacteristics suitable for application to an organic material layerused in an organic light emitting device. This will be described indetail, below.

The steric core structure of the compound of Formula 1, for convenienceof explanation, can be divided into two portions, A and B, as shown inthe following Formula.

The compound of Formula 1 has the steric core structure in which a planeA meets with a plane B at right angles around X, and conjugation doesnot occur between the A and B portions around X. Furthermore, since onenitrogen atom is positioned among three aryl groups in the plane B,conjugation is limited in the plane B.

The conjugation length of the compound has a close relationship with anenergy band gap. In detail, the energy band gap is reduced as theconjugation length of the compound increases. As described above, sincea conjugation structure is limited in the core structure of the compoundof Formula 1, the core structure has a large energy band gap.

As described above, in the present invention, various substituent groupsare introduced to R1 to R15 positions and Z1 and Z2 positions of thecore structure having the large energy band gap so as to producecompounds having various energy band gaps. Generally, it is easy tocontrol the energy band gap by introducing substituent groups into acore structure having a large energy band gap, but it is difficult tosignificantly control the energy band gap by introducing substituentgroups into a core structure having a small energy band gap.Furthermore, in the present invention, it is possible to control HOMOand LUMO energy levels of the compound by introducing varioussubstituent groups into the R1 to R15 positions and the Z1 and Z2positions of the core structure.

Additionally, by introducing various substituent groups into the corestructure, compounds having intrinsic characteristics of the substituentgroups can be synthesized. For example, substituent groups, which arefrequently applied to hole injection layer materials, hole transportlayer materials, light emitting layer materials, and electron transportlayer materials which are used during the production of the organiclight emitting device, are introduced into the core structure so as toproduce substances capable of satisfying requirements of each organicmaterial layer. For example, since the core structure of the compound ofFormula 1 includes the arylamine structure, it has an energy levelsuitable for the hole injection and/or hole transport materials in theorganic light emitting device. In the present invention, the compoundhaving the proper energy level is selected depending on the substituentgroup among the compounds represented by Formula 1 to be used in theorganic light emitting device, thereby it is possible to realize adevice having a low actuating voltage and a high light efficiency.

Furthermore, various substituent groups are asymmetrically introducedinto the core structure (for example, the A portion is introduced intoone side of the core structure) so as to precisely control the energyband gap, improve interfacial characteristics with organic materials,and apply the compound to various fields.

As well, if the number of amine contained in the substituent group A isset to 1 (if Z1 and Z2 are hetero aromatic amine compounds, the numberof nitrogen contained in them is not counted), it is possible toprecisely control the HOMO and LUMO energy levels and the energy bandgap, and on the other hand interfacial characteristics with the organicmaterials is improved and thereby make it possible to apply the compoundto various fields.

Additionally, various substituent groups are introduced into the stericstructure of the compound of Formula 1 using spiro bonding to controlthe three-dimensional structure of the organic material so as tominimize π-π interaction in the organic material, thereby formation ofexcimers is prevented.

With respect to the energy band gap and the energy level, for example,since the compound of Formula 2-1, in which arylamine is introduced intothe hole transport material or the hole injection material of thestructure of Formula 1, has HOMO of 5.47 eV, it has an energy levelsuitable for the hole injection layer or the hole transport layer.Meanwhile, the compound of Formula 2-2 has the band gap of 3.18 eV,which is still larger than that of NPB, typically used as the holetransport layer material, thus it has a LUMO value of about 2.29 eV,which is considered to be very high. If a compound having a high LUMOvalue is used as the hole transport layer, it increases the energy wallof LUMO of the material constituting the light emitting layer to preventthe movement of electrons from the light emitting layer to the holetransport layer. Accordingly, the above-mentioned compound improves thelight emission efficiency of the organic light emitting device so thatefficiency is higher than that of conventionally used NPB (HOMO 5.4 eV,LUMO 2.3 eV, and energy band gap 3.1 eV). In the present invention, theenergy band gap is calculated by a typical method using a UV-VISspectrum.

As well, the compound of Formula 1 has stable redox characteristics.Redox stability is estimated using a CV (cyclovoltammetry) method. Forexample, if oxidation voltage is repeatedly applied to the compound ofFormula 2-2, oxidation repeatedly occurs at the same voltage and thecurrent amount is the same. This means that the compound has excellentstability to oxidation.

Meanwhile, since the compound of Formula 1 has a high glass transitiontemperature (Tg), it has excellent thermal stability. For example, theglass transition temperature of the compound of Formula 2-2 is 129° C.,which is still higher than that of conventionally used NPB (Tg: 96° C.).Such increase in thermal stability is an important factor providingactuating stability to the device.

Furthermore, the compound of Formula 1 may be used to form the organicmaterial layer using a vacuum deposition process or a solution coatingprocess during the production of the organic light emitting device. Inconnection with this, illustrative, but non-limiting, examples of thesolution coating process include a spin coating process, a dip coatingprocess, an inkjet printing process, a screen printing process, a sprayprocess, and a roll coating process.

For example, the compound of Formula 2-2 has excellent solubility to apolar solvent, such as xylene, dichloroethane, or NMP, which is usedduring the production of the device, and forms a thin film very wellthrough the process using a solution, thus the solution coating processmay be applied to produce the device. Additionally, a light emittingwavelength of a thin film or a solid formed using the solution coatingprocess is typically shifted to a longer wavelength due to interactionbetween molecules, in comparison with a light emitting wavelength in asolution state. Little shift in the wavelength occurs in the compoundhaving the structure shown in Formula 1.

Tertiary alcohol, which is produced by a reaction of a lithiated aryland keto group, is heated in the presence of an acid catalyst to form ahexagonal cyclic structure while water is removed, thereby producing thecompound having a spiro structure according to the present invention.The above-mentioned procedure for producing the compound is well knownin the art, and those skilled in the art can change the productionconditions during the production of the compound of Formula 1. Theproduction will be described in detail in the preparation exampleslater.

The organic light emitting device of the present invention can beproduced using known materials through a known process, modified only inthat at least one layer of organic material layer(s) includes thecompound of the present invention, that is, the compound of Formula 1.

The organic material layer(s) of the organic light emitting deviceaccording to the present invention may have a single layer structure, oralternatively, a multilayered structure in which two or more organicmaterial layers are layered. For example, the organic light emittingdevice of the present invention may comprise a hole injection layer, ahole transport layer, a light emitting layer, an electron transportlayer, and an electron injection layer as the organic material layer(s).However, the structure of the organic light emitting device is notlimited to this, but may comprise a smaller number of organic materiallayers.

Furthermore, the organic light emitting device of the present inventionmay be produced, for example, by sequentially layering a firstelectrode, organic material layer(s), and a second electrode on asubstrate. In connection with this, a physical vapor deposition (PVD)method, such as a sputtering method or an e-beam evaporation method, maybe used, but the method is not limited to these.

A method of producing the compound of Formula 1 and the production ofthe organic light emitting device using the same will be described indetail in the following preparation examples and examples. However, thefollowing preparation examples and examples are set forth to illustrate,but are not to be construed to limit the present invention.

MODE FOR THE INVENTION

A better understanding of a method of producing an organic compoundrepresented by Formula 1 and the production of an organic light emittingdevice using the same may be obtained in light of the followingpreparation examples and examples which are set forth to illustrate, butare not to be construed to limit the present invention.

In order to produce the compound represented by Formula 1, any one ofthe compounds of the following Formulae, a to c, may be used as astarting material.

Preparation Example 1 Preparation of a Starting Material Represented byFormula a

Carbazole (1.672 g, 10 mmol), 1-bromo-2-iodobenzene (1.5 ml, 12 mmol),potassium carbonate (K₂CO₃, 2.7646 g, 20 mmol), copper iodide (CuI, 95mg, 0.5 mmol), and 25 ml of xylene were refluxed in a nitrogenatmosphere. After cooling to normal temperature was conducted, a productwas extracted with ethyl acetate, water was removed with anhydrousmagnesium sulfate (MgSO₄), and the solvent was removed at a reducedpressure. The resulting product was passed through a silica gel columnusing a hexane solvent to produce a compound, the solvent was removed ata reduced pressure, and vacuum drying was conducted to produce theresulting white solid compound (800 mg, 25% yield). MS: [M+H]⁺=323.

Preparation Example 2 Preparation of a Starting Material Represented byFormula b

4.19 g of starting material represented by Formula a (13 mmol) weredissolved in 50 ml of purified THF, and 4.8 ml of n-BuLi (2.5 M inhexane, 12 mmol) were slowly dropped thereon at −78° C. Stirring wasconducted at the same temperature for 45 min, and 2.59 g of2-bromo-9-fluorenone (10.0 mmol) were added thereto. After stirring wasconducted at the same temperature for 1 hour, the temperature was raisedto normal temperature, stirring was carried out for an additional 2hours, and the reaction was completed in a NH₄Cl aqueous solution. Anorganic material was extracted with ethyl ether, water was removedtherefrom, and an organic solvent was removed to produce yellow solid.The produced solid was dispersed in ethanol, stirred, filtered, andvacuum dried to produce 4.5 g of intermediate material. The intermediatesolid was dispersed in 40 ml of acetic acid, 12 drops of concentratedsulfuric acid were added thereto, and reflux was conducted for 3 hours.After cooling to normal temperature, the resulting solid was filtered,washed with ethanol, and vacuum dried to create 3.98 g of product (82.2%yield). MS: [M+H]⁺=484.

Preparation Example 3 Preparation of a Starting Material Represented byFormula c

The starting material represented by Formula c (5.0 g, 10.32 mmol) wascompletely dissolved in 40 ml of THF, 4-chloro-phenylboronic acid (2.42g, 15.48 mmol), 2M potassium carbonate solution,tetrakis(triphenylphosphine)palladium(0) (0.31 mmol, 0.36 g), and 10 mlof ethanol were added thereto, and reflux was conducted for 24 hours.After the reaction was completed, cooling to normal temperature wasconducted, and filtration was conducted. Washing was conducted withwater and ethanol, several times. Recrystallization was conducted withethanol, and vacuum drying was conducted to produce a compound (4.97 g,yield 93%). MS: [M+H]⁺=515.

Example 1 Preparation of the Compound Represented by Formula 2-2

The compound of Formula b (3.0 g, 6.19 mmol) andN-phenyl-1-naphthylamine (1.5 g, 6.81 mmol) were dissolved in 50 ml oftoluene, sodium-tert-butoxide (0.89 g, 9.3 mmol), bis(dibenzylideneacetone)palladium(0) (Pd(dba)₂, 0.07 g, 0.124 mmol), and 50 wt %tri-tert-butylphosphine (0.09 ml, 0.186 mmol) were added thereto, andreflux was conducted in a nitrogen atmosphere for 2 hours. Distilledwater was added to the reaction solution to complete the reaction, andthe organic layer was extracted. A column separation process wasconducted using a solvent of n-hexane and tetrahydrofuran(n-hexane/THF=4/1), recrystallization was conducted with ethanol, andvacuum drying was conducted to produce a compound (2.0 g, yield 52%).MS: [M+H]⁺=622.

Example 2 Preparation of the Compound Represented by Formula 3-2

The compound of Formula c (5.0 g, 9.69 mmol) andN-phenyl-1-naphthylamine (2.3 g, 10.5 mmol) were dissolved in 50 ml oftoluene, sodium-tert-butoxide (3.02 g, 31.5 mmol), bis(dibenzylideneacetone)palladium(0) (Pd(dba)₂, 0.217 g, 0.121 mmol), and 50 wt %tri-tert-butylphosphine (0.13 ml, 0.315 mmol) were added thereto, andreflux was conducted in a nitrogen atmosphere for 2 hours. Distilledwater was added to the reaction solution to complete the reaction, andthe organic layer was extracted. A column separation process wasconducted using a solvent of n-hexane and tetrahydrofuran(n-hexane/THF=4/1), recrystallization was conducted with ethanol, andvacuum drying was conducted to produce a compound (4.2 g, yield 62%).MS: [M+H]⁺=698.

Example 3 Production of an Organic Light Emitting Device

A glass substrate (corning 7059 glass), on which ITO (indium tin oxide)was applied to a thickness of 1000 Å to form a thin film, was put indistilled water, in which a detergent was dissolved, and washed usingultrasonic waves. In connection with this, a product manufactured byFischer Inc. was used as the detergent, and distilled water was producedby filtering twice using a filter manufactured by Millipore Inc. AfterITO was washed for 30 min, ultrasonic washing was conducted twice usingdistilled water for 10 min. After the washing using distilled water wascompleted, ultrasonic washing was conducted using isopropyl alcohol,acetone, and methanol solvents, and drying was then conducted. Next, itwas transported to a plasma washing machine. The substrate was drywashed using oxygen plasma for 5 min, and then transported to a vacuumevaporator.

Hexanitrile hexaazatriphenylene (hereinafter, referred to as “HAT”) ofthe following Formula was vacuum deposited to a thickness of 500 Å byheating on a transparent ITO electrode, which was prepared through theabove procedure, so as to form an anode including an ITO conductivelayer and an N-type organic material.

The compound of Formula 2-2 (400 Å) was vacuum deposited thereon to forma hole transport layer. Alq3 was vacuum deposited to a thickness of 300Å on the hole transport layer to form a light emitting layer. Anelectron transport layer material of the following Formula was depositedto a thickness of 200 Å on the light emitting layer to form an electrontransport layer.

Lithium fluoride (LiF) having a thickness of 12 Å and aluminum having athickness of 2000 Å were sequentially deposited on the electrontransport layer to form a cathode.

In the above procedure, the deposition speed of an organic material wasmaintained at 0.3-0.8 Å/sec. Furthermore, lithium fluoride and aluminumwere deposited at speeds of 0.3 Å/sec and 1.5-2.5 Å/sec, respectively,on the cathode. During the deposition, a vacuum was maintained at1-3×10⁻⁷.

The resulting device had an electric field of 9.74 V at a forwardcurrent density of 100 mA/cm², and a spectrum having a light efficiencyof 1.63 lm/W. The operation and light emission of the device at theabove-mentioned actuating voltage mean that the compound of Formula 2-2,which formed the layer between the hole injection layer and the lightemitting layer, functions to transport holes.

Example 4 Production of an Organic Light Emitting Device

The procedure of example 3 was repeated to produce a device except thatthe compound of Formula 3-2 was used instead of the compound of Formula2-2 as a hole transport layer.

The resulting device had an electric field of 8.59 V at a forwardcurrent density of 100 mA/cm², and a spectrum having a light efficiencyof 1.79 lm/W. The operation and light emission of the device at theabove-mentioned actuating voltage mean that the compound of Formula 3-2,which formed the layer between the hole injection layer and the lightemitting layer, functions to transport holes.

INDUSTRIAL APPLICABILITY

The compound of the present invention can be used as an organic materiallayer material, particularly, hole injection and/or transport materialsin an organic light emitting device, and when applied to an organiclight emitting device it is possible to reduce the actuating voltage ofthe device, to improve the light efficiency thereof, and to improve thelifespan of the device through the thermal stability of the compound.

1. An organic light emitting device, comprising: a first electrode;organic material layer(s) comprising a light emitting layer, wherein atleast one layer of the organic material layer(s) includes the compoundof Formula 1; and a second electrode; wherein the first electrode, theorganic material layer(s), and the second electrode form layeredstructure,

wherein X is C or Si, A is —NZ1Z2; Y is a bond; bivalent aromatichydrocarbons; bivalent aromatic hydrocarbons which are substituted withat least one substituent group selected from the group consisting ofnitro, nitrile, halogen, alkyl, alkoxy, and amino groups; a bivalentheterocyclic group; or a bivalent heterocyclic group which issubstituted with at least one substituent group selected from the groupconsisting of nitro, nitrile, halogen, alkyl, alkoxy, and amino groups;Z1 and Z2 are each independently hydrogen; aliphatic hydrocarbons havinga carbon number of 1-20; aromatic hydrocarbons; aromatic hydrocarbonswhich are substituted with at least one substituent group selected fromthe group consisting of the nitro, nitrile, halogen, alkyl, alkoxy,amino, aromatic hydrocarbon, and heterocyclic groups; a silicon groupsubstituted with aromatic hydrocarbons; a heterocyclic group; aheterocyclic group which is substituted with at least one substituentgroup selected from the group consisting of the nitro, nitrile, halogen,alkyl, alkoxy, amino, aromatic hydrocarbon, and heterocyclic groups; athiophenyl group which is substituted with hydrocarbons having a carbonnumber of 1-20 or aromatic hydrocarbons having a carbon number of 6-20;or a boron group which is substituted with aromatic hydrocarbons; R1 toR11 are each independently hydrogen, a substituted or unsubstitutedalkyl group, a substituted or unsubstituted alkoxy group, a substitutedor unsubstituted alkenyl group, a substituted or unsubstituted arylgroup, a substituted or unsubstituted arylamine group, a substituted orunsubstituted heterocyclic group, an amino group, a nitrile group, anitro group, a halogen group, an amide group, or an ester group, and R1to R11 may form aliphatic or hetero condensation rings along withadjacent groups; and R12 to R15 are each independently hydrogen, asubstituted or unsubstituted alkyl group, a substituted or unsubstitutedalkoxy group, a substituted or unsubstituted alkenyl group, asubstituted or unsubstituted aryl group, a substituted or unsubstitutedheterocyclic group, an amino group, a nitrile group, a nitro group, ahalogen group, an amide group, or an ester group, and R12 to R15 mayform aliphatic or hetero condensation rings along with adjacent groups;and R7 and R8 may be directly connected to each other, or may form acondensation ring along with a group selected from the group consistingof O, S, NR, PR, C═O, CRR′, and SiRR′, wherein R and R′ are eachindependently or collectively hydrogen, a substituted or unsubstitutedalkyl group, a substituted or unsubstituted alkoxy group, a substitutedor unsubstituted alkenyl group, a substituted or unsubstituted arylgroup, a substituted or unsubstituted arylamine group, a substituted orunsubstituted heterocyclic group, a nitrile group, an amide group, or anester group, and may form a condensation ring to form a spiro compound.2. The organic light emitting device as set forth in claim 1, wherein R7and R8 of Formula 1 form a condensation ring along with a group selectedfrom the group consisting of O, S, NR, PR, C═O, CRR′, and SiRR′.
 3. Theorganic light emitting device as set forth in claim 1, wherein thecompound of Formula 1 is any one of compounds of Formulae 2 to 5:


4. The organic light emitting device as set forth in claim 1, wherein Aof Formula 1 is any one of following groups:


5. The organic light emitting device as set forth in claim 1, whereinthe organic material layer(s) comprise a hole transport layer, and thehole transport layer includes the compound of Formula
 1. 6. The organiclight emitting device as set forth in claim 1, wherein the organicmaterial layer(s) comprise a hole injection layer, and the holeinjection layer includes the compound of Formula
 1. 7. The organic lightemitting device as set forth in claim 1, wherein the organic materiallayer(s) comprise a layer which both injects and transports holes andwhich includes the compound of Formula 1.